feat(ui): add vietnamese to language picker

Closes #7384

Author: psychedelicious

invokeai/frontend/web/src/features/system/components/SettingsModal/SettingsLanguageSelect.tsx

@@ -31,6 +31,7 @@ const optionsObject: Record<Language, string> = {
   sv: 'Svenska',
   tr: 'Türkçe',
   ua: 'Украї́нська',
+  vi: 'tiếng Việt',
   zh_CN: '简体中文',
   zh_Hant: '漢語',
 };

invokeai/frontend/web/src/features/system/store/types.ts

@@ -22,6 +22,7 @@ const zLanguage = z.enum([
   'sv',
   'tr',
   'ua',
+  'vi',
   'zh_CN',
   'zh_Hant',
 ]);